From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS, T_DKIMWL_WL_HIGH,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id AF8F6C32789 for ; Fri, 2 Nov 2018 18:54:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7720620848 for ; Fri, 2 Nov 2018 18:54:42 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="IZNlPgzp" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 7720620848 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linuxfoundation.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730954AbeKCEC4 (ORCPT ); Sat, 3 Nov 2018 00:02:56 -0400 Received: from mail.kernel.org ([198.145.29.99]:58672 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726150AbeKCECz (ORCPT ); Sat, 3 Nov 2018 00:02:55 -0400 Received: from localhost (5356596B.cm-6-7b.dynamic.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 2B44F2082D; Fri, 2 Nov 2018 18:54:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1541184879; bh=mZZMH5FThFic2QSRIZ+hqKN5JgGMMIwBDanQJvgo+7w=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=IZNlPgzpg2p/nWtXEx3dtPr8a4W7flMb+hNV9gr2WbmSHfppoZ+PnysKTQSyOW2mJ 4j9ZkW7diwP++JcfXPqvFoXz2pdCHi89Ob3rLfGnBj6C3coEkrhoNqt0t4r+hrDeL2 1qOorHZ0s9ACJ7rsF+62sVzYHRCpODVZB5tuILng= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Eric Dumazet , syzbot , "David S. Miller" Subject: [PATCH 4.14 117/143] ipv6: mcast: fix a use-after-free in inet6_mc_check Date: Fri, 2 Nov 2018 19:35:02 +0100 Message-Id: <20181102182907.205964718@linuxfoundation.org> X-Mailer: git-send-email 2.19.1 In-Reply-To: <20181102182857.064326086@linuxfoundation.org> References: <20181102182857.064326086@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: Eric Dumazet [ Upstream commit dc012f3628eaecfb5ba68404a5c30ef501daf63d ] syzbot found a use-after-free in inet6_mc_check [1] The problem here is that inet6_mc_check() uses rcu and read_lock(&iml->sflock) So the fact that ip6_mc_leave_src() is called under RTNL and the socket lock does not help us, we need to acquire iml->sflock in write mode. In the future, we should convert all this stuff to RCU. [1] BUG: KASAN: use-after-free in ipv6_addr_equal include/net/ipv6.h:521 [inline] BUG: KASAN: use-after-free in inet6_mc_check+0xae7/0xb40 net/ipv6/mcast.c:649 Read of size 8 at addr ffff8801ce7f2510 by task syz-executor0/22432 CPU: 1 PID: 22432 Comm: syz-executor0 Not tainted 4.19.0-rc7+ #280 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x1c4/0x2b4 lib/dump_stack.c:113 print_address_description.cold.8+0x9/0x1ff mm/kasan/report.c:256 kasan_report_error mm/kasan/report.c:354 [inline] kasan_report.cold.9+0x242/0x309 mm/kasan/report.c:412 __asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:433 ipv6_addr_equal include/net/ipv6.h:521 [inline] inet6_mc_check+0xae7/0xb40 net/ipv6/mcast.c:649 __raw_v6_lookup+0x320/0x3f0 net/ipv6/raw.c:98 ipv6_raw_deliver net/ipv6/raw.c:183 [inline] raw6_local_deliver+0x3d3/0xcb0 net/ipv6/raw.c:240 ip6_input_finish+0x467/0x1aa0 net/ipv6/ip6_input.c:345 NF_HOOK include/linux/netfilter.h:289 [inline] ip6_input+0xe9/0x600 net/ipv6/ip6_input.c:426 ip6_mc_input+0x48a/0xd20 net/ipv6/ip6_input.c:503 dst_input include/net/dst.h:450 [inline] ip6_rcv_finish+0x17a/0x330 net/ipv6/ip6_input.c:76 NF_HOOK include/linux/netfilter.h:289 [inline] ipv6_rcv+0x120/0x640 net/ipv6/ip6_input.c:271 __netif_receive_skb_one_core+0x14d/0x200 net/core/dev.c:4913 __netif_receive_skb+0x2c/0x1e0 net/core/dev.c:5023 netif_receive_skb_internal+0x12c/0x620 net/core/dev.c:5126 napi_frags_finish net/core/dev.c:5664 [inline] napi_gro_frags+0x75a/0xc90 net/core/dev.c:5737 tun_get_user+0x3189/0x4250 drivers/net/tun.c:1923 tun_chr_write_iter+0xb9/0x154 drivers/net/tun.c:1968 call_write_iter include/linux/fs.h:1808 [inline] do_iter_readv_writev+0x8b0/0xa80 fs/read_write.c:680 do_iter_write+0x185/0x5f0 fs/read_write.c:959 vfs_writev+0x1f1/0x360 fs/read_write.c:1004 do_writev+0x11a/0x310 fs/read_write.c:1039 __do_sys_writev fs/read_write.c:1112 [inline] __se_sys_writev fs/read_write.c:1109 [inline] __x64_sys_writev+0x75/0xb0 fs/read_write.c:1109 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x457421 Code: 75 14 b8 14 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 34 b5 fb ff c3 48 83 ec 08 e8 1a 2d 00 00 48 89 04 24 b8 14 00 00 00 0f 05 <48> 8b 3c 24 48 89 c2 e8 63 2d 00 00 48 89 d0 48 83 c4 08 48 3d 01 RSP: 002b:00007f2d30ecaba0 EFLAGS: 00000293 ORIG_RAX: 0000000000000014 RAX: ffffffffffffffda RBX: 000000000000003e RCX: 0000000000457421 RDX: 0000000000000001 RSI: 00007f2d30ecabf0 RDI: 00000000000000f0 RBP: 0000000020000500 R08: 00000000000000f0 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000293 R12: 00007f2d30ecb6d4 R13: 00000000004c4890 R14: 00000000004d7b90 R15: 00000000ffffffff Allocated by task 22437: save_stack+0x43/0xd0 mm/kasan/kasan.c:448 set_track mm/kasan/kasan.c:460 [inline] kasan_kmalloc+0xc7/0xe0 mm/kasan/kasan.c:553 __do_kmalloc mm/slab.c:3718 [inline] __kmalloc+0x14e/0x760 mm/slab.c:3727 kmalloc include/linux/slab.h:518 [inline] sock_kmalloc+0x15a/0x1f0 net/core/sock.c:1983 ip6_mc_source+0x14dd/0x1960 net/ipv6/mcast.c:427 do_ipv6_setsockopt.isra.9+0x3afb/0x45d0 net/ipv6/ipv6_sockglue.c:743 ipv6_setsockopt+0xbd/0x170 net/ipv6/ipv6_sockglue.c:933 rawv6_setsockopt+0x59/0x140 net/ipv6/raw.c:1069 sock_common_setsockopt+0x9a/0xe0 net/core/sock.c:3038 __sys_setsockopt+0x1ba/0x3c0 net/socket.c:1902 __do_sys_setsockopt net/socket.c:1913 [inline] __se_sys_setsockopt net/socket.c:1910 [inline] __x64_sys_setsockopt+0xbe/0x150 net/socket.c:1910 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe Freed by task 22430: save_stack+0x43/0xd0 mm/kasan/kasan.c:448 set_track mm/kasan/kasan.c:460 [inline] __kasan_slab_free+0x102/0x150 mm/kasan/kasan.c:521 kasan_slab_free+0xe/0x10 mm/kasan/kasan.c:528 __cache_free mm/slab.c:3498 [inline] kfree+0xcf/0x230 mm/slab.c:3813 __sock_kfree_s net/core/sock.c:2004 [inline] sock_kfree_s+0x29/0x60 net/core/sock.c:2010 ip6_mc_leave_src+0x11a/0x1d0 net/ipv6/mcast.c:2448 __ipv6_sock_mc_close+0x20b/0x4e0 net/ipv6/mcast.c:310 ipv6_sock_mc_close+0x158/0x1d0 net/ipv6/mcast.c:328 inet6_release+0x40/0x70 net/ipv6/af_inet6.c:452 __sock_release+0xd7/0x250 net/socket.c:579 sock_close+0x19/0x20 net/socket.c:1141 __fput+0x385/0xa30 fs/file_table.c:278 ____fput+0x15/0x20 fs/file_table.c:309 task_work_run+0x1e8/0x2a0 kernel/task_work.c:113 tracehook_notify_resume include/linux/tracehook.h:193 [inline] exit_to_usermode_loop+0x318/0x380 arch/x86/entry/common.c:166 prepare_exit_to_usermode arch/x86/entry/common.c:197 [inline] syscall_return_slowpath arch/x86/entry/common.c:268 [inline] do_syscall_64+0x6be/0x820 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe The buggy address belongs to the object at ffff8801ce7f2500 which belongs to the cache kmalloc-192 of size 192 The buggy address is located 16 bytes inside of 192-byte region [ffff8801ce7f2500, ffff8801ce7f25c0) The buggy address belongs to the page: page:ffffea000739fc80 count:1 mapcount:0 mapping:ffff8801da800040 index:0x0 flags: 0x2fffc0000000100(slab) raw: 02fffc0000000100 ffffea0006f6e548 ffffea000737b948 ffff8801da800040 raw: 0000000000000000 ffff8801ce7f2000 0000000100000010 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8801ce7f2400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8801ce7f2480: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc >ffff8801ce7f2500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8801ce7f2580: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc ffff8801ce7f2600: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 Signed-off-by: Eric Dumazet Reported-by: syzbot Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/ipv6/mcast.c | 16 ++++++++-------- 1 file changed, 8 insertions(+), 8 deletions(-) --- a/net/ipv6/mcast.c +++ b/net/ipv6/mcast.c @@ -2412,17 +2412,17 @@ static int ip6_mc_leave_src(struct sock { int err; - /* callers have the socket lock and rtnl lock - * so no other readers or writers of iml or its sflist - */ + write_lock_bh(&iml->sflock); if (!iml->sflist) { /* any-source empty exclude case */ - return ip6_mc_del_src(idev, &iml->addr, iml->sfmode, 0, NULL, 0); + err = ip6_mc_del_src(idev, &iml->addr, iml->sfmode, 0, NULL, 0); + } else { + err = ip6_mc_del_src(idev, &iml->addr, iml->sfmode, + iml->sflist->sl_count, iml->sflist->sl_addr, 0); + sock_kfree_s(sk, iml->sflist, IP6_SFLSIZE(iml->sflist->sl_max)); + iml->sflist = NULL; } - err = ip6_mc_del_src(idev, &iml->addr, iml->sfmode, - iml->sflist->sl_count, iml->sflist->sl_addr, 0); - sock_kfree_s(sk, iml->sflist, IP6_SFLSIZE(iml->sflist->sl_max)); - iml->sflist = NULL; + write_unlock_bh(&iml->sflock); return err; }